The present invention relates to a sliding rail assembly for drawer and more specifically, to a sliding rail assembly auto locking structure, which assures positive locking of the sliding rail assembly and smooth motion of the sliding rail assembly.
FIGS. 1 and 2 illustrate a sliding rail assembly auto locking structure used in a sliding rail assembly 9 for drawer. This sliding rail assembly auto locking structure comprises a holder base 91, a spring member 92, a slide 93, and a push block 941 at the inner sliding rail 94. Because the spring member 92 is mounted in a spring chamber 912 inside the holder base 91, the spring member 92 is forced to rub against the inside wall of the spring chamber 912 when it is alternatively compressed and stretched. Therefore, the spring member 92 wears quickly with use. Further, it is difficult to replace the spring member 92 when the spring member 92 is damaged. Further, the slide 93 has two guide rods 931 and 932 for guiding reciprocating motion of the slide 93 in a sliding groove 911 inside the holder base 91. The sliding groove 911 has a downwardly extending front retaining groove portion 9111 for receiving one guide rod 931. When the user arranges the drawer or touches the drawer accidentally, the guide rod 931 of the slide 93 may be forced out of the front retaining groove portion 9111 of the sliding groove 911, causing the slide 93 to be pulled backwards by the spring member 92. In this case, the auto locking structure fails to function normally, and the drawer cannot be pushed to the rear side. U.S. Pat. Nos. 5,207,781 and 5,302,016 and PCT WO 01/8279A2 have same drawbacks. Further, the spring member 93 has one end hooked on one guide rod 931 of the slide 93 and is kept in a oblique manner, i.e., the spring member 93 is not horizontally stretched and compressed, resulting in instability of the reciprocating motion of the slide 93 and short working life of the spring member 93. Further, because the slide 93 vibrates heavily when it is pulled directly by the spring member 92 during its return stroke.
Therefore, it is desirable to provide a sliding rail assembly auto locking structure that eliminates the aforesaid drawbacks.
The present invention has been accomplished under the circumstances in view. According to one aspect of the present invention, the sliding rail assembly auto locking structure is comprised of a holder base, a swivel hook, a slide, two return springs, and a hydraulic cylinder. When an arched block of the swivel hook is approaching a recess in the holder base for positioning, the arched block does not fall to the recess directly. At this time, oblique guide grooves of the swivel hook are moved over associating guide blocks of the holder base to guide the arched block into the recess slowly and smoothly, and therefore the inner sliding rail of the sliding rail assembly is moved with the drawer smoothly without vibration.
According to another aspect of the present invention, the oblique guide grooves of the swivel hook are positively supported on the guide blocks of the holder base when the arched block entered the recess of the holder base, thereby holding the swivel hook in a tilted position where the swivel hook is disengaged from the actuating block at the inner sliding rail for allowing the drawer to be pulled to the outside of the desk. Because the oblique guide grooves of the swivel hook are positively supported on the guide blocks of the holder base, vibration of the drawer caused accidentally by an external force or an earthquake does not cause the swivel hook to be moved away from the guide blocks and pulled backwards by the return springs and the slide.
According to still another aspect of the present invention, the return springs are suspending at two sides outside the holder base. When the return springs are stretched or compressed, the return springs do not rub against the outside wall of the holder bas. Therefore, the return springs are durable in use, and replacement of the return springs can easily be performed.
According to still another aspect of the present invention, the swivel hook is coupled to the slide and has the two guide rods respectively slidably coupled to the longitudinal sliding slots of the holder base, and the slide is connected to the return springs and has the two guide blocks thereof respectively slidably coupled to the longitudinal sliding slots of the holder base. This arrangement assures smooth reciprocation of the swivel hook and the slide in the holder base. Further, the hydraulic cylinder buffers the return stroke of the slide, eliminating vibration and noise.